ABSTRACT
Agricultural management influences the soil ecosystem by affecting its physicochemical properties, residues of pesticides and microbiome. As vineyards grow crops with the highest incidence of pesticides, the aim of this study was to evaluate the impact of conventional and sustainable management systems of vineyards from DOP Ribeiro on the soil's condition. Samples from soils under three different management systems were collected, and the main soil physicochemical properties were evaluated. A selection of 50 pesticides were investigated by liquid chromatography with tandem mass spectrometry. The bacterial and fungal microbiomes were characterized through amplicon sequencing. The results show that organic agriculture positively influences soil pH and the concentration of some nutrients compared to conventional management. Our microbiome analysis demonstrated that transitioning from conventional to organic management significantly improves several BeCrop® indexes related to key microbial metabolism and soil bio-sustainability. Such a transition does not affect soil alpha diversity, but leads to a higher interconnected microbial network structure. Moreover, differential core genera and species for each management system are observed. In addition, the correlation of the microbiome with geographical distance is evidence of the existence of different microbial terroirs within DOP Ribeiro. Indeed, sustainable management leads to higher nutrient availability and enhances soil health in the short term, while lowering pesticide usage.
ABSTRACT
Atmospheric mercury (Hg) is largely assimilated by vegetation and subsequently transferred to the soil by litterfall, which highlights the role of forests as one of the largest global Hg sinks within terrestrial ecosystems. We assessed the pool of Hg in the aboveground biomass (leaves, wood, bark, branches and twigs), the Hg deposition flux through litterfall over two years (by sorting fallen biomass in leaves, twigs, reproductive structures and miscellaneous) and its accumulation in the soil profile in a deciduous forest dominated by Betula alba from SW Europe. The total Hg pool in the aboveground birch biomass was in the range 532-683 mg ha-1, showing the following distribution by plant tissues: well-developed leaves (171 mg ha-1) > twigs (160 mg ha-1) > bark (159 mg ha-1) > bole wood (145 mg ha-1) > fine branches (25 mg ha-1) > thick branches (24 mg ha-1) > newly sprouted leaves (20 mg ha-1). The total Hg deposition fluxes through litterfall were 15.4 and 11.7 µg m-2 yr-1 for the two years studied, with the greatest contribution coming from birch leaves (73 %). In the soil profile, the pool of Hg in the mineral soil (37.0 mg m-2) was an order of magnitude higher than in the organic horizons (1.0 mg m-2), mostly conditioned by parameters such as soil bulk density and thickness, total C and N contents and the presence of certain Al compounds.
